Loulan is believed __________ over by sandstorms gradually from AD200 to AD400.
— What is 10% of 800,000,000?— It is _____.
He promised _____ back in a few minutes.
Beethoven was not birth deaf. He began to go deaf, _____ he grew older.
Martin was sick with a strange fever; _______, he could neither eat nor sleep.
I was in the _____ position with having completely forgotten her name.